Shift-over valve



A. G. WINCHESTER SHIFT-OVER VALVE Oct. 9, 1951 2 Sheets-Sheet l FiledAug. 2, 1944 Gttomeg JXW Olct. 9, 1951 A. G. WINCHESTER 2,570,896

` SHIFT-OVER VALVE Brmentor Ms Cttorneg Pa'tented ct. 9, 1951 LAlbertGrvin Winchester,--Baltimore, Md.-, as4 signor toGerotor MayCorporation, acorporation of Maryland Application August 2, 1944,"SerialNo.' v547,789

1o claims. l

My inventionrelates'to valves; and more particularly concerns a nuidcontrol 'valve forfcontrolling the manner of'operation of a fluidysystem.

An object of-myinvention is to provide ahydraulic valve of the generalclass described, which is unitary, compact, self-contained, and of smallspace requirements; which is simple, sturdy, displays long wear, highefficiency, 'and a high 'degree of reliability; which requires only asmall number of movable parts, and theseV of simple and sturdy type, andhence involves low cost, both initially and in maintenance; rvand whichvalve is balanced, both dynamically'and hydrostatically.

Another object is'to provideA a hydraulic valve, adapted'for controllingAthe separate and alternate energization of ak vmain 'hydraulic Ksystemfrom a plurality of 'separate sourcesrof *fluidtransmitted energy, asdesired, and'w'hich nis capable of accomplishing this-objective *withoutdanger of connecting these energy'sources in the system at the sametime. f

Other'objects willin part be vobvioi'is'a'nd in part pointed outhereinafter,V during the development ofthe following description. y

My invention accordingly resides inthe several parts, elements andfeatures of construction,l and in the relation of each of the 1Vsameto'oneor more of thev others Vas described *herein andas -more fully dened'in-the accompanying claims.

In the accompanying drawings, -wherein`-I-'dis close apreferred-embodiment-of my invention,

Figures 1, l2 and Sfare longitudinal-sectional views, respectively`showing the `valve fininitial position, intermediate, and .n'al.or-endposition;'Figure 3, forclarity, also showinga manual return meansfor restoring an includedzelement of the Valve from final end .positionto initial limit position. Through conventional means, not shown, thismanual return means is physically associated with a bleeder valve shownat the upper left of 'the 4casing in the three views.

As conducive to a more thoroughzunderstanding of certain featuresof myinvention vit may be noted that more and more importance,ifrom apractical standpoint, has attached to Athe use of hydraulic Vsystems forenergy Ltransfer. AOne such instance, fornpurposes of villustration, kisdisclosed in copen'ding application `for ',Letters Patent of the United.States,LSerial"No. 547,788, led of even datefherewith, entitledAuxiliary Ship Steering Apparatus, and Linthe names Aof Albert RivingtonStone and `Albert .Girvin 'Winchester, now Patent :2,512,119 yof .June.20, .1950,

wherein a hydraulic system is employed lfor operating 'the steeringrudder of a ship. Ordinarily `a lmain pump installation energizes thedisclosedsystem. `YUpon the-pump becoming disabled for Iany reason,however, as for example storm-damage, -damage ordestruction by enemyaction, orthe like, shift-over vto suitable stand- Pby or auxiliaryfequipment is made .possible `by meansof a valve.

Despite Ywhether the -stand-by Vequipment Vbe either arranged Ainopposed or additive relation tothe main-pumps, or otherhydraulicsourceofenergy-it'islimportantto ensure that the'standby equipment'is not cutinto the hydraulic system until the `mainenergysonrceis disconnected,and that the stand-by equipment, when it is cut into operation, isconnected in :theproper direction.

Accordingly, an 'important 'object of my .invention is to avoid4certaindisadvantages and diiculties attendant in the lprior art, and`vto provide simple and 'inexpensive' hydraulic Valve means whichensure, an extremely eli'icacious manner, that associated 'main andstandlby energizing .equipment will not be connected Vinto a hydrauliccontrol system atthe same time, and that one ksuch kenergizing meanswill be lcut out of the systembeforelthe other -is cut in.

rReferring now more particularly'to the` embodiment of myinventionvdrisclosed in thenthree,

views of the drawings, casing II) of manganese bronze or other suitablemetal is longitudinally bored at I I and I2, these boresbeingparallelfand disposed one above thevother. In the central,longitudinal Verticalsectional Views employed in the drawingsQonlyathin, longitudinal extent of the Wall Iii ofoasing .I0 serves toseparate the bores II :and I2. 'End plates I3 and Iltexlvtendtransversely .across Aopposite .ends of casing Y I0 .and serve `toVclose loff the ends of Vbores II and I2.

Liners I5, I6 preferably kare `provided fat the cation, within thecasing, between port I1 and bores II and I2.

Valve elements slidable in their respective bores II and I2 are providedin the form of pistons I9 and 20. The two pistons respectively compriseshank portions 2Ia, 2lb, and shank portions 22d, 22h, all ofcomparatively reduced section, spaced between a plurality of headportions 23a, 23h, 23c and 24a, 24h, 24o, respectively, of largerdiameter. These head portions 23a, 24a, etc., serve effectively andeciently the dual functions oi bearing elements cooperating withcorresponding liners I5, I6 to provide snug, smooth and gliding tbetween the bearing elements, with entire absence of detrimentalbinding; and as well, to seal the corresponding annular chambers orrecesses 25a, 25h and 26a, 2Gb, formed vbetween liners I5, I6, headportions 23a, 23o, 23o and 24a, 241), 24C, and shanks 2|, 22. It ispreferred to make the pistons of steel hardened and ground to size.

In the upper part of casing IIJ, through liner I5, a set of three ports21a, 21h, and 2'Ic let laterally into bore I I along the length thereof.Similarly, on the lower part of the casing, a set of three ports 28a,28h and 28C let laterally into bore I2, along the length thereofpreferably at points directly opposite the irst three portsrespectively. It will be noted that in the preferred embodiment thesethree ports, of each of the two sets of ports, after letting into thecorresponding bores II and I2, exend completely and transverselytherearound, in the form of annular grooves or recesses, to establishconditions of dynamic balance when iiuid is introduced through saidgrooves.

Within dividing wall I between bores II and I2 (and to the right ofpiston header portions 23h, 2Gb when the like pistons are in theirinitial limit position in Figure 1), I provide a port 29,interconnecting bores II and I2. The purpose of this bore 29 willshortly be developed.

The ports within each set of three ports are so related to each otherand to the ports of the other set, and to corresponding like pistonswith ltheir alternating shank and head portions of reduced and enlargedsection, that in the initial limit position of the pistons shown inFigure 1, and corresponding in this preferred embodiment to the restposition where main energizing equipment, for example, is connected intothe hydraulic system, the following relationships and connections areestablished: The head portions 23h, 24h block 01T port 29 from any ofthe ports of the two sets of lateral ports. Head portions 23o, 24e,moreover, effectively block the internal port 29 from end port Il.Simultaneously annular chambers 25a, 26a, defined respectively by linerI5, shank 2Ia and head portions 23a, 23h, and by liner I6, shank 22a,and head portions 24a, 24h, serve to interconnect corresponding lateralports 2lb and 21e, and 28h and 28e, respectively, of each set, whileenlarged head portions 23a, 24a of the piston blocks the correspondinglateral ports 21a, 28a. For purposes of illustration it will be assumedthat a main pump is connected at ports 2Ic and 28o and that these portsthus represent low and high pressure sides of the pump respectively.

The valve position represented in Figure 1 of the drawing permits thefluid from main energy source to pass between 2lb, 2Ic and 28h, 28owithout interference, while lines 21a, 28a connected as cross intake andoutput sides respectively of stand-by equipment are eicctively blocked.It will also be assumed for purposes of illustration 4 that ports 2lband 28h are connected with high and low pressure sides of a fluid motorsuch as a hydraulic ram Or rams or other load to be operated as by themain or emergency pumps depending upon the end limit position of thepistons.

The head portions 23a, 231), 23c and 24a, 24h,

24e of the piston valves are provided with annular grooves or channels30, 3| arranged peripherally thereabout in their outer cylindricalsurfaces, and with lead-off or bleeder bores 32, 33 disposed in thebottoms of these grooves or traps and leading off in turn to axial orlongitudinal channels in pistons I9 and 20.

It has therefore been observed that the wall IIJ' separating the twobores I I and I2 terminates short of endplate I4. It should also benoted that the wall I0 terminates at a point considerably short of endplate I3, so that at this other or left end of the casing I0, the boresII and I2 let into a common compartment 35 having considerably largerdimensions.. The opposite ends of the pistons adjacent this common spaceA36, and indicated for convenience at 2 I, 22, are interconnected bysuitable means which here takes the form of an equalizing bar or yoke 34extending transversely therebetween. This yoke 34 ensures that the twolike pistons I9, 20 move together as a unit, and to this extent, servesas a tie-in means.. The yoke also serves eilectively as a medium throughwhich forces may be transmitted for moving the pistons, all in a mannerwhich will be fully developed.

Enlarged sleeve 35 centrally embraces yoke 34, and is securely attachedtransversely across the end of a connecting rod 31 which extendscentrally through end plate I3, to the exterior.

Connecting rod 31, moving with pistons I9, 20, reciprocates in end plateI3, between initial and end limit positions. For each limit position, Iprovide yielding latch or detent means for holding the connecting rod,and hence the piston assembly, against accidental movement. While thedetent means may assume any of a variety of diierent forms withoutdeparting from the spirit of my invention, in the present embodiment Iprovide paired annular grooves 38, 39 on the periphery of the connectingrod 31 a distance apart equal to the extent of the piston travel. In endplate I3, in any suitable manner, I provide a vertical bore or channel40, in which is seated a ball or similar detent 4I, spring-pressed bycoiled spring 42 into the cooperating annular recesses 38, 39. Theserecesses, spaced apart in the manner hereinbefore specied, arepositioned along connecting rod 31 so that when the pistons are in theirinitial limit position, at the right end of casing I0 in the drawings,recess 38 will be directly below bore 4U and will receive and be latchedby ball detent 4I, and when the pistons are in their final or end limitposition, at the left of casing I0 in the drawings, recess 39 will bedisposed beneath and latched by ball detent l I. The detention providedby the aforesaid latching means is, as has been said, yielding innature, and will permit positive shifting of the valve elements wheneverdesired. This eiTectively prevents accidental shifting of iluttering ofthe valve elements during operation and consequent disturbance of thesystem performance.

In the design of end plate I3 I provide such thickness of material,including base I3', that recesses 38,y 39 during the longitudinalreciprocation of connecting rod 31, are maintained entirely within theconfines of the plate. This simplies constructionisomewhat, and requiresonly that the `iit between rod -31 and end plate I3 be snug, smooth, andnicely machined, and that proper packing glands, notl shown, be providedto seal the bore in which the rod 31 is recessed, from fluid withinchamber 36.

The operation of ports 21a, 2lb, 2Ic and28a, 28h, 28e has been describedfor the initial or rest position of the valve. In the co-pendingapplication this corresponds to the period of energization from a mainpump, andto deactivation `of available stand-by equipment. c

When it is desired to change over vfrom one energy source to another,however, pressure iiuid from a suitable source isy admitted through portI'I and space I8 to bores II and I2, at the right ends, Figures 1through 3, of the pistons I9 and 20. In the co-pending application, thisiiuid courses through the port II from the stand-b57 equipment, as thelatter is brought into operation. The pistons thus press aside theyieldable detent means referred to, and move asa unit, smartly to theleft in the drawings, from the initial limit position to the nal or endlimit position shown in Figure 3. Unitary movement of the pistons isensured preferably by 'applying substantially the same total'iiuidpressure on the adjacent piston ends. In the present instance unitaryaction is achieved by employing pistons I9 and 20, of like cross-sectionand by distributing fluid -through space I8 at like pressures on theadjacent piston ends While the pistons are tied together by yoke 34.

It has been suggested at an earlier point herein that unless provisionto the contrary is made, there is danger of inadvertently throwing bothmain and auxiliary stand-by power equipment into the line at the sametime. To remove Yany possibility of this occurrence, I arrange thelateral ports and the head portions of the pistons so that as thepistons move from their initial end limit position under the influenceof the impelling uid entering at II, the circuits `or connectionsestablished in the initial end condition are rbroken before continued-movement of the valve element to the left establishes connectionsbetween ports 21a, 2lb and between ports 28a, 28h as well as across-connection between ports 21C, 218e through internal port 29.

In the co-pending application, uid flow Yacross ports 27C, 29 and 28C isequivalent to Yiiuid shortcircuit of the main pump. This effectivelyremoves any possibility of the main pump being cut into the hydraulicsystem at the same time as the stand-by equipment, for independent-connections are established between the stand-by equipment and thehydraulic system. Of course, for entirely practical reasons, the mainpump should be de-energized as soon as possible after being cut out ofthe line.

VIt is of course to be undersood that the transitory phase or stage ofoperation in which the movement of the pistons from one limit-'positionto another is continuous and of comparatively short duration, thevalves, through connecting rod 3l, being yieldingly latched in eitherlimit position.

Shortly after the straight-through connection of ports 2'Ic, 29 and 28chas been established, continued movement of the valve'pistons to theleft opens, across each set of lateralvports, connections between theports 21a and 2lb, through chamber 25a, on the one hand, and'betweenports 28a and 28h, through chamber `2Ia, onthe other hand. Thus, withineach set of ports, ports 21a, 2lb are paired, and'ports-28a,2-8bfarepaired;an'd

to connect the stand-by equipment to the line,

and thence to ship-steering rams or the like. At this point, theconnection between ports 21e, 29 and 28e remains established.

` The head portions 23a, 24a of the two piston valves vare designed ofsuch width as to ensure the intermediate straight-through connectionbetween ports 2'Ic, 29 and Zac before the ports 21a, 2lb and 28a, 28hare Vconnected in pairs within each set of ports. That is, to illustratein one instance, head portion 23h will uncover-port 21e beforehead-portion 23a will uncover port 21a.

In the final limit position of the piston valves, shown in Figure 3,ball detent 4I engages in annular recess 39, -yieldingly locking thevalve elements in this position, In the Vintermediate position of Figure2, on the contrary, the ball I is intermediate the recesses 33 and 39,and the Valve elements are free to complete their travel in eitherdirection.

While it is entirelyv possible to provide hydraulic means for restoringthe valve elements from their iinal limit position in Figure 3,corresponding to system operation from stand-by equipment, to theirinitial position shown in Figure 1, corresponding to operation from mainpumps, to do so involves unnecessarily great complication and complexityof construction. This would increase first cost, dimensions, andoperating expenses. Accordingly,l I find it advantageous to employmanual return means, and I have shown such means in Figure 3.

In Figure 3, I provide an operating arm or crank d3 having a convex camportion 44 and an end e5 having an eye 46, which engages about a pivotpin lll'. While this pin el is shown only schematically in Figure 3 asbeing disposed in space, it is of course apparent that this can becarried in any suitable manner, as by a bracket or arm struck fromcasing I0 or end plate I3. Cam dll cooperates with stud IIS on the endof connecting rod 31. It will be noted that eye i6 is disposeduppermost, while arm i3 is designed to be'swung downwardly. Thus, duringa working stroke, the arm swings counter-clockwise about pin @1 as apivot. Cam M engages stud QS, and bodily, through sleeve 35 andequalizing bar or yoke 34, restores the pistons I9, 2o from their endlimit position, shown in Figure 3, to their initial limit position,shown in Figure l. In so doing, the ball detent @I is pushed upwardly,against the yielding urge of spring 52, out of engagement with recess39. Ball lil remains in its uppermost position, until the piston valvesreach their position of Figure 3, Iwhereupon the ball seats in recess38.

While either limit position is `being reached, some uid will remain inbores I I and I2 in advance of the pistons. Thus in reaching the Valveposition represented in Figure l, fluid will remain in chamber 36, andwhile obtaining the setting shown in Figure 3, fluid will be in chambersAB, 50. It is necessary to remove this advanced fiuid before movement ofthe pistons can be accomplished. To this end, I provide a novel type ofbleeder means, at the upper left of casing lo.

A longitudinal sleeve 5I is let into casing lil, parallel to and abovebore I I, through end plate I3. This sleeve is shouldered internallyintermediate its length, at 52, so that a comparatively wide 'bore 53 isprovided at the right of this shoulder, while a relatively narrow bore54 is provided'atthe left thereof. This shoulder .'52

also serves as a seat for ball 55 pressedby coil spring 56 disposedwithin the bore 53.

A lateral channel 51 extends from chamber 36 through the casingl andthrough sleeve l, to the exterior. This channel passes across sleeve 5|through reduced-section port 58, so as to provide a straight-throughconnection. The charnber 36 is always open through channel 51.

Within reduced section bore 54 a plunger 59 is received for snug slidingfit therein. This plunger is adapted for movement with arm 43, by meansof suitable linkage or other connection, as shown at of Fig. 3. On theforward end of the plunger adjacent valve seat 52, there is a shankportion 60 of reduced section. This shank portion is adapted to contactball valve 55 through seat 52, and to displace the same against spring56. The reduced section shank portion 60 permits uninterruptedstraight-through connection between chamber 35 and the exterior, throughbore 51.

The linkage between arm 43 and plunger 59 is such that the latter isactuated to displace the ball 55 from seat 52 when the pistons are beingrestored from their Figure 3 position to their Figure l position.

A threaded cap 6I having a small bore 62 therein seats in the right endof sleeve 5l, and as an abutment retains spring 55. Bleeder channel 63in casing I0 connects between the right end of sleeve 5l in the figuresand vertical bleeder line 64 which leads to the exterior and thence toend port l1, through connections not shown.

When the pistons are moved to Figure 3 position, the fluid in 36 isforced through 51, 58, around shaft 65, 58 and 51 to the exterior, asfor example, to a suitable storage reservoir, not shown. Upon movementof the pistons to Figure 1 position, the crank arm 43 is manipulated.This slides plunger 59 to the right, and shaft 55 unseats ball 55against the force of spring 56, in counter movement to the direction offlow of fluid entering through bleeder line 64. Thus as pistons I9, 2limove to the right, fluid expelled through chambers 49, 50 passes throughconduit I8, end port l?, bleeder line 64, bleeder channel 63, bore 62,bore 53, around unseated ball 55, through valve seat 52, toreduced-section bore 54, and thence out through upper transverse bores56 and 51 to the storage reservoir or the like.

It will be noted that the valve described herein requires two pistonsrather than a single piston. There is more than mere duplication ofparts involved in the design of these pistons. Consideration will showthat to effect the mechanical and functional equivalent of thisconstruction with but a single piston would require an elongated,cumbersome and complicated assembly, totally unsatisfactory from apractical standpoint.

As it is, my new valve is neat, compact and comparatively simple. Itssmall number of moving parts, carefully machined and fitted, ensures ahigh degree of durability and long wear. The new assembly effectivelyensures that power sources are separately and alternately thrown upon ahydraulic line, and that simultaneous cut-in is avoided. I have found,for example, that my new construction contributes immeasurably to thesuccessful operation of the system set forth in the said co-pendingapplication. The new valve is in hydrostatic balance, due to the bleederline relief construction and in dynamic balance, due to the drain offmeans for leakage uid in the head portions of the piston valves and tothe fact that the lateral ports are in the form of annular groovesextending completely around the bores Il and I2.

The use of liners I5, I6 and sleeve 5I makes reconditioning andoverhauling comparatively simple and inexpensive.

As many possible embodiments may be made of my invention and as manychanges may be made in the embodiments hereinbefore set forth, it is tobe understood that all matter described herein is to be interpreted asillustrativeV and not as a limitation.

I claim:

A 1. As a new article of manufacture, a hydraulic valve comprising, incombination, a valve casing with lateral inlet and outlet ports thereinand having a longitudinal bore extending therein, said *casing having afurther port at one end thereof opening into said bore, a valve elementslidable in said bore for controlling said lateral ports by uid pressureat said end port, manuallyoperated means on said casing and connectedwith said valve element for restoring the same after movement thereof byfluid from the end port, and bleeder control means actuated by saidmanually-operated means and connected with said longitudinal bore inadvance of said slidable valve element, for receiving and passing excessfluidexpelled through said casing.

2. A hydraulic valve comprising, in combination, a longitudinally boredValve casing, and a plurality of valve pistons slidable in said boredcasing between two positions of control, said casing including acorresponding plurality of sets of at least three ports each lettinginto said bore, the ports of each set being so disposed relative to eachother and to said plurality of pistons that in one control position ofsaid pistons, two ports of each set are connected one to the other whilethe third is blocked off, and in the other limit position astraight-through connection is provided between like ports of said setsof ports and within each set of ports the other ports thereof are openedto each other in pairs.

3. A hydraulic valve comprising, in combination, a valve casing having aplurality of pistons slidable longitudinally back and forth thereinbetWeen two limit positions with an end port for admitting fluid to movesaid pistons and a corresponding plurality of sets of at least threeports letting into said casing, the ports of each set being so disposedrelative to each other and to said pistons that in one limit position ofthe latter paired ports of each set are opened to each other, the thirdport in each thereof being blocked oi, While in an intermediate positionsaid pistons break off the first-mentioned connections and establish across-connection between a single port of each of said paired ports.

4. A hydraulic Valve comprising, in combination, a valve casing having apair of pistons slidable longitudinally therein between two limitpositions with an end port for admitting uid to move said valve elementout of adjacent limit position and a corresponding pair of sets of atleast three ports letting into said casing, the ports of each set beingso disposed relative to each other and to said pair of pistons that inone limit position of the latter connections are established such thatpaired ports of each set are opened to each other while the third portis blocked, and in the other limit position of the pair of pistons across-connection is provided between like ports of said sets of portsand within each set of ports the remaining ports are opened 9 to eachother; and spring-pressed ball detent means cooperating withcomplementary-shaped portions of the pair of pistons to hold the latteryieldingly in the lirnit positions.

5. In combination, a valve casing having a pair of pistons slidablebetween two end limit positions with an end port in said casing foradmitting pressure fluid to said pistons to displace the same and acorresponding pair of sets of ports letting laterally through saidcasing, each set comprising at least three ports the lateral ports ofeach set and the pair of pistons being so disposed that in one positionof the latter paired ports of each set are open to each other while thethird ports are blocked, and in the other limit position a cross'-connection is provided between like ports of said sets of ports andwithin each set of ports the remaining ports are open tc each other; anda bleeder valve in said casing and connecting with each end thereof forbleeding off excess uid from that end of the casing towards which thepair of pistons is displaced.

6. A hydraulic valve comprising the combination of a valve casing havingpaired longitudinal bores therein; and two pistons movable together onein each bore between initial and end limit positions, said casingincluding at least one port leading into corresponding ends of the boresfor admitting fluid to move said pistons, and two sets of at least threeports, the individual sets letting laterally through said casing intothe individual bores with said lateral ports and said pistons being sorelated that in initial position the pistons establish a connectionbetween paired adjacent ports of each set while blocking the third port,and in end position break said first-mentioned connections to establisha cross-connection of ports of the two sets through a port between saidbores and interconnection, within each set, of the other two ports inpairs,

7. A hydraulic valve comprisingthe combination of a valve casing havingpaired longitudinal bores therein; two pistons movable together, one ineach bore, between initial and limit positions; and an equalizing pinconnecting said pistons together near corresponding ends thereof, saidcasing including at least one end port leading into corresponding endsofthe bores for admitting fluid to move said pistons, and two sets of atleast three ports, the individual sets letting laterally through saidcasing into the individual bores with said lateral ports and saidpistons being so related that in initial position the pistons establisha connection between paired adjacent ports of each set' while blockingthe third port, and in end position break said first-mentionedconnections to establish a cross-connection of ports of the two setsthrough a port between said bores and interconnection, within each set,of the other two ports in pairs.

8. A hydraulic valve comprising the combination of a valve casing havingpaired longitudinal bores; two pistons one in each bore and movabletogether between initial and end limit positions; a yoke interconnectingsaid pistons near the ends remote from said end port; andmanually-operable means for applying force on said yoke to restore saidpistons to initial positions, said casing including at least one endport opening through said casing into corresponding ends of the boresfor admitting fluid to move the pistons and two sets of at least threeports, the individual sets letting laterally through said casing intothe individual bores with said lateral ports and said pistons being sorelated that in initial position the pistons establish a connectionbetween paired adjacent ports of each set while blocking the third port,and in end position break said firstmentioned connections to establish across-connection between like ports of the two sets through a portbetween the bores and interconnect, within each set, the other two portsin pairs.

9. A hydraulic valve comprising the combination of a valve casing havingpaired longitudinal bores therein; liners in said bores serving asbearing surfaces; and two pistons one in'each bore and movable togetherbetween initial and end 1 limit positions, said casing including atleast one end port opening through said casing into corresponding endsof the bores for admitting iiuid to move the pistons and two sets of atleast three ports, the individual sets letting laterally through saidcasing into the individual bores with said lateral ports and saidpistons being so related that in initial position the pistons establisha connection between paired adjacent ports of each set while blockingthe third port, and in end position break said mst-mentioned connectionsto establish a cross-connection between like ports of the two setsthrough a port between the bores and interconnection, within each set,of the other two ports in pairs.

10. In combination, a longitudinally-bored valve casing; piston meansslidable therein; a bleeder valve assembly mounted in said casing, saidbleeder valve comprising a sleeve defining a longitudinal bore, ashouldered valve seat therein, a spring-pressed ball normally seating onsaid valve seat to close said bleeder valve, a manuallyactuatedplungerforrunseating said ball, van outer port in said sleeve andcasing, and an inlet port in said sleeve and casing; and connectionsfrom said respective inlet and outlet ports to opposite ends of saidcasing bore and on opposite sides of said piston, one connection beingin constant communication with said outlet port and the other connectionopening to said outlet port only upon unseating said ball valve.

ALBERT GIRVIN WINCHESTER.

REFERENCES CITED The following references are of record in the le of'this patent:

UNITED STATES PATENTS Number Name Date 98,153 Deck Dec. 21, 1869 196,106Anderson Oct. 16, 1877 559,881 Ahrens May 12, 1896 908,224 Eckland Dec.29, 1908 1,339,939 Alter May 11, 1920 1,431,101 Dineen Oct. 3, 19221,554,673 Heath Sept. 22, 1925 1,937,077 West Nov. 28, 1933 1,938,758Ernst Dec. 12, 1933 2,012,065 Haas Aug. 2-0, 1935 2,176,594 NordstromOct. 17, 1939 2,184,793 Clench Dec. 26, 1939 2,238,768 Berglund Apr. 15,1941 2,326,487 Overbeke Aug. 10, 1943 2,342,450 Campbell Feb. 22, 1944FOREIGN PATENTS Number Country Date 687,466 France Apr. 28, 1930

